Visualization and Estimation of Vibratory Disturbance in Vocal Fold Scar Using High-Speed Digital Imaging

Functional Analysis of Injectable Substance Treatment on Surgically Injured Rabbit Vocal Folds

OBJECTIVES

The objective of this study was to evaluate the efficacy of immediate injection treatments of dexamethasone, hyaluronic acid (HA)/gelatin (Ge) hydrogel and glycol-chitosan solution on the phonatory function of rabbit larynges at 42 days after surgical injury of the vocal folds, piloting a novel ex vivo phonatory functional analysis protocol.

METHODS

A modified microflap procedure was performed on the left vocal fold of 12 rabbits to induce an acute injury. Animals were randomized into one of four treatment groups with 0.1 mL injections of dexamethasone, HA/Ge hydrogel, glycol-chitosan or saline as control. The left mid vocal fold lamina propria was injected immediately following injury. The right vocal fold served as an uninjured control. Larynges were harvested at Day 42 after injection, then were subjected to airflow-bench evaluation. Acoustic, aerodynamic and laryngeal high-speed videoendoscopy (HSV) analyses were performed. HSV segments of the vibrating vocal folds were rated by three expert laryngologists. Six parameters related to vocal fold vibratory characteristics were evaluated on a Likert scale.

RESULTS

The fundamental frequency, one possible surrogate of vocal fold stiffness and scarring, was lower in the dexamethasone and HA/Ge hydrogel treatment groups compared to that of the saline control (411.52±11.63 Hz). The lowest fundamental frequency value was observed in the dexamethasone group (348.79±14.99 Hz). Expert visual ratings of the HSV segments indicated an overall positive outcome in the dexamethasone treatment group, though the impacts were below statistical significance.

CONCLUSION

Dexamethasone injections might be used as an adjunctive option for iatrogenic vocal fold scarring. An increased sample size, histological correlate, and experimental method improvements will be needed to confirm this finding. Results suggested a promising use of HSV and acoustic analysis techniques to identify and monitor post-surgical vocal fold repair and scarring, providing a useful tool for future studies of vocal fold scar treatments.

Application of the HRES 5562 Camera Using the HSDI Technique in the Diagnosis of Glottal Insufficiencies in Teachers

OBJECTIVE

Teachers are the largest group of professional voice users with predispositions to functional or organic changes in the larynx. The dysfunction of intrinsic muscles of the larynx frequently occurs which leads to changes in parameters of quality of voice (dysphonia). The aim of the study is the assessment of parameters of vocal folds vibrations, Mucosal Wave morphology, Glottal Closure Type and Open Quotient (OQ) using High Speed (HS) camera and High Speed Digital Imaging (HSDI) technique in teachers with disorders of voice quality classified in GRBAS scale in glottal insufficiencies.

MATERIAL AND METHOD

The study included group of 50 teachers of both genders, working in primary and secondary education units for 15 years, without systemic diseases with disorders of quality of voice confirmed by the results in GRBAS scale assessment. Vocal folds vibrations were assessed with HS camera by R. Wolf and HSDI technique. Rigid endoscope with 90^o optics by the same company was used in the study. Vocal folds vibrations were registered with the speed of 4000 frames/sec. Regularity, symmetry of vibrations, Mucosal Wave (MW) morphology as well as Glottal Closure Type were assessed. Numerical value of OQ was determined in anterior, middle and posterior segment of the glottis during phonation.

RESULTS

Assessment of real vibrations of vocal folds revealed irregularity, mean asymmetry of vibrations, MW reduction as well as glottal insufficiency, the most frequently (96%), in the middle segment - type E according to European Laryngological Society, less frequently (4%) - type E+C. The highest value of OQ (average 0.98) was registered in the middle segment of the glottis. In GRBAS scale, significant dysphonia has been registered, classified as G₃R₃B₃A₃ without the features of voice strain - S₀.

CONCLUSION

In group of teachers with extensive professional experience, glottal insufficiency in the middle segment was registered the most frequently which was confirmed by high values of OQ in this region obtained with HSDI technique. What is more, irregularity, mean asymmetry and asynchrony of vibrations with MW reduction were registered which confirmed the existence of glottal insufficiency in this group. GRBAS scale was useful in preliminary evaluation of dysphonia and its severity, however, the diagnosis of its clinical form was possible only with visualization of the larynx and objective parameters obtained with HSDI.

Multivariate Analysis of Vocal Fold Vibrations in Normal Speakers Using High-Speed Digital Imaging

INTRODUCTION

Little is known about the normal variations in vocal fold vibrations. We conducted a prospective study on normal subjects using high-speed digital imaging (HSDI) to elucidate key parameters regarding age/gender-related normal variations.

METHODS

Forty-six healthy adult volunteers were divided into young (aged ≤35 years) male, young female, elderly (aged ≥65 years) male, and elderly female subgroups. HSDI data of sustained phonation of /i/ at a comfortable pitch and loudness were obtained, and vibratory parameters were calculated using the visual-perceptual rating, laryngotopography, digital kymography, and glottal area waveform. Multivariate analysis was then performed on these parameters to clarify the subgroup-specific key parameters.

RESULTS

Four key parameters were identified from a total of 83: one from visual perceptual rating and three from laryngotopography. Subgroup analyses showed that posterior-to-anterior longitudinal phase difference (PD) and high fundamental frequency (F₀) were specific to young female participants. A low F₀ was specific to young male participants. Large anterior-to-posterior longitudinal PD and its left-right difference were specific to elderly male participants. There were no key parameters for elderly female participants.

CONCLUSIONS

Methods that can assess F₀ and longitudinal PD, such as visual-perceptual rating and laryngotopography, were effective in the evaluation of normal vocal fold vibrations and their variations.

Evaluation of Voice and Vocal Fold Vibration after Thyroidectomy Using Two-Dimensional Scanning Digital Kymography and High-Speed Videolaryngoscopy

OBJECTIVE

Vocal dysfunction is one of the major factors that affect the health-related quality of life of patients after thyroidectomy. Conventionally, voice changes after thyroidectomy have been evaluated by videostroboscopy and acoustic analysis. Recently, two-dimensional scanning digital kymography (2D DKG) and high-speed videolaryngoscopy (HSV) have been developed and have shown usefulness in accurately evaluating vocal fold vibration. This study aimed to evaluate changes of vocal fold vibration and voice after thyroidectomy using 2D DKG and HSV.

MATERIALS AND METHODS

We evaluated the voice and vocal fold movement of 24 female patients who underwent thyroidectomy in a single tertiary hospital from December 2018 to October 2019. We obtained serial 2D DKG and HSV data one day before thyroidectomy, and 1 week and 1 month after surgery. We analyzed the peak glottal area of HSV, amplitude symmetry index, phase symmetry index, and open quotient using the 2D DKG data. The parameters were calculated at three levels of the vocal fold (line 1=anterior, line 2=middle, line 3=posterior). In the same period, we performed a voice analysis evaluating voice frequency, jitter, shimmer, and noise to harmonic ratio. We also assessed maximum phonation time and subjective voice changes with voice handicap index-10 questionnaires.

RESULTS

Highest frequency (F-high), frequency range (F-range), and fundamental frequency (F0) decreased at 1 week and 1 month after thyroidectomy compared with preoperative values (P = 0.003, 0.004, <0.001 and P = 0.002, 0.015, 0.001 at 1 week and 1 month, respectively). The open quotient of 2D DKG in lines 1 and 2 increased at 1 week after thyroidectomy (P = 0.011, 0.006) and recovered to preoperative levels at 1 month postoperatively (P = 0.189, 0.153). Other quantitative measures by 2D DKG and HSV did not show significant changes between the preoperative and postoperative periods. In a correlation analysis between vocal parameters from the acoustic analysis and the values obtained from 2D DKG and HSV, significant negative correlations were observed between peak glottal area and three factors (F-high, F-range, and F0) at 1 month after surgery (r = -0.589, -0.529, -0.708; P = 0.002, 0.008, <0.001, respectively). There were positive correlations between phase symmetry indexes in lines 1 and 2 and shimmer at 1 week after thyroidectomy (r = 0.489, 0.425; P = 0.015, 0.038, respectively). Phase symmetry index in line 3 showed a significant negative correlation with maximum phonation time at both 1 week and 1 month after surgery (r = -0.497, -0.439; P = 0.013, 0.032, respectively). However, there was no correlation between total score on the voice handicap index-10 questionnaires and quantitative measurements of vocal fold vibration.

CONCLUSION

2D DKG and HSV may provide important information on vocal fold vibratory patterns after thyroidectomy, and measurements made with them were correlated with maximal phonation time and acoustic parameters such as F-high, F-range, F0, shimmer.

Visual and Automatic Evaluation of Vocal Fold Mucosal Waves Through Sharpness of Lateral Peaks in High-Speed Videokymographic Images

INTRODUCTION

The sharpness of lateral peaks is a visually helpful clinical feature in high-speed videokymographic (VKG) images indicating vertical phase differences and mucosal waves on the vibrating vocal folds and giving insights into the health and pliability of vocal fold mucosa. This study aims at investigating parameters that can be helpful in objectively quantifying the lateral peak sharpness from the VKG images.

METHOD

Forty-five clinical VKG images with different degrees of sharpness of lateral peaks were independently evaluated visually by three raters. The ratings were compared to parameters obtained by automatic image analysis of the vocal fold contours: Open Time Percentage Quotients (OTQ) and Plateau Quotients (PQ). The OTQ parameters were derived as fractions of the period during which the vocal fold displacement exceeds a predetermined percentage of the vibratory amplitude. The PQ parameters were derived similarly but as a fraction of the open phase instead of a period.

RESULTS

The best correspondence between the visual ratings and the automatically derived quotients were found for the OTQ and PQ parameters derived at 95% and 80% of the amplitude, named OTQ₉₅, PQ₉₅, OTQ₈₀ and PQ₈₀. Their Spearman's rank correlation coefficients were in the range of 0.73 to 0.77 (P < 0.001) indicating strong relationships with the visual ratings. The strengths of these correlations were similar to those found from inter-rater comparisons of visual evaluations of peak sharpness.

CONCLUSION

The Open time percentage and Plateau quotients at 95% and 80% of the amplitude stood out as the possible candidates for capturing the sharpness of the lateral peaks with their reliability comparable to that of visual ratings.

Evaluation of clinical value of videokymography for diagnosis and treatment of voice disorders

This study aimed at determining the clinical value of videokymography (VKG) as an additional tool for the assessment of voice disorders. 105 subjects with voice disorders were examined by an experienced laryngologist. A questionnaire was used to specify diagnosis, diagnostic confidence, and treatment recommendations before and after VKG. The first part of questionnaire was filled by the laryngologist for each patient after routine ear-nose-throat evaluation, including stroboscopy, the second part after the subsequent VKG examination. In 31% of subjects VKG confirmed the stroboscopic diagnosis, in 44% it made the diagnosis more accurate, in 20% there was adjustment of the treatment, and in 5% it was not found diagnostically useful. After VKG the diagnostic confidence increased in 68% of the subjects. VKG may help clinicians to take some important treatment decisions and may be recommended to be performed in patients, where clinicians are uncertain about diagnosis and treatment.

Evaluation of the combined use of narrow band imaging and high-speed imaging to discriminate laryngeal lesions

BACKGROUND AND OBJECTIVE

Laryngeal lesions are usually investigated by microlaryngoscopy, biopsy, and histopathology. This study aimed to evaluate the combined use of Narrow Band Imaging (NBI) and High-Speed Imaging (HSI) in the differentiation of glottic lesions in awake patients.

STUDY DESIGN

Prospective diagnostic study.

MATERIALS AND METHODS

Thirty-six awake patients with 41 glottic lesions were investigated with both NBI and HSI, and the suspected diagnoses were compared to the histopathological results of tissue biopsies taken during subsequent microlaryngoscopies. Of the 41 lesions, 28 were primary lesions and 13 recurrent lesions after previous laryngeal pathologies.

RESULTS

Sensitivity, specificity, positive predictive value, and negative predictive value in the differentiation between benign/premalignant and malignant lesions with both NBI and HSI accounted to 100.0%, 79.4%, 50.0%, and 100.0%. Sensitivities and specificities were 100.0% and 85.7% for HSI alone, and 100.0% and 79.4% for NBI alone. Regarding only primary lesions the results were generally better with sensitivities and specificities of 100% and 81% for NBI, 100% and 84.2% for HSI and 100% and 85.7% for the combination of both methods, respectively.

CONCLUSION

NBI and HSI both seem to be promising adjunct tools in the differentiation of various laryngeal lesions in awake patients with high sensitivities. Specificities, however, were moderate but could be increased when using NBI and HSI in combination in a subgroup of patients with only primary lesions. Although both methods still have limitations they might ameliorate the evaluation of suspicious laryngeal lesions in the future and could possibly spare patients from repeated invasive tissue biopsies. Lasers Surg. Med. 49:609-618, 2017. © 2017 Wiley Periodicals, Inc.